The present invention relates to a dynamic cache partition device and method which is applicable to a multi-core system with multiple cores. The device of the present invention comprises at least one multi-core processor and at least one shared cache that is shared by multiple processing cores, wherein the shared cache comprises multiple cache lines and is divided into multiple sub-caches, and the multiple sub-caches comprise at least one private cache that is used for each single processing core and at least one public sub-cache that is shared by all the processing cores; an apparatus, configured to monitor shared cache hit information for each processing core of the multiple processing cores; and an apparatus, configured to determine whether the cache line should be assigned to the public sub-cache or assigned to the private sub-cache that is associated with one of the multiple processing cores. The dynamic cache partition device and method provided by the present invention have a plurality of advantages, for example, improving data sharing performance, simplifying data consistency in a multi-core system, and using the cache more effectively.